Patients with Chronic Superficial Venous Insufficiency (CSVI) usually present reflux in one or several saphenous trunks, and bulging varicose tributaries and perforators.
Saphenous trunks can be removed by surgery, chemical or thermal ablation.
Concerning thermal ablation of saphenous trunk, reference is made to U.S. Pat. No. 7,753,871-B which discloses a Steam Vein Sclerosis (SVS) device for delivering thermal energy to the venous wall, which results in vein wall fibrotic retraction and its subsequent definitive occlusion or obliteration. Thermal or steam ablation combines the advantages of thermal and chemical ablation. Steam ablation of saphenous trunks has been clinically used for several years with success. The device heats sterile water into steam and delivers the steam into the vein for coagulation of the vein in patients with superficial venous reflux. The steam heats the vein wall transferring thermal energy that raises the temperature of the vascular wall. The thermal energy destroys the intima and causes contraction and thickening of the collagen fibers within the adventitia and especially the media. The diameter of the vein is thus greatly reduced by contraction and thickening of collagen fibrils and also by the spasm induced by the increased temperature. These phenomena result in the occlusion of the venous lumen. Such a concept is faster and simpler and allows a homogenous diffusion of the heat. Moreover, pulsated steam is the best way to convey energy to tissues: it is an excellent heat conductor and avoids carbonization encountered with other thermal approaches. The device is composed of equipment and disposables and consists in 3 main parts:                a cold water pulse generator that produces micro pulses (80 μl) of pressurized sterile water. The generator is composed of a pneumatic piston, a hydraulic pump and a sterile water flask. The pistons produce two phases: the filling up of the hydraulic pump with sterile water and the injection of this sterile water in the hand-piece/pipe.        a hand piece/pipe that transforms pulses of water in pulses of steam. The heating element is incorporated into the hand piece, close to the distal end, allowing minimal energy loss.        an endovenous metallic microtube for distributing the steam into the vein.        
In practice, the injection unit is in addition combined with a water storage bag. The microtube for distributing the steam into the vein of internal diameter equal to 150 μm and external diameter equal to 350 μm. This microtube is connected to the distal end of the hand piece by any appropriate means. The microtube has transverse openings on a blunt end or a central opening on a non blunt end. The vein to be treated is punctured using a needle positioned in a small catheter about 5 cm long, the surface of which has been Teflon® treated, the needle being withdrawn after inserting the catheter at the surface of the skin. The microtube is introduced into the catheter until the distal end of the microtube reaches the end of the vein to be treated. The generator then sends pulses of cold water into the hand piece, which transforms these pulses into steam at a temperature of about 200° C. and the steam then passes through the microtube to its distal end. Using the markings on the surface of the microtube, the operator progressively withdraws the microtube giving one or more pulses per centimeter depending on the diameter of the vessel.
The means of distributing the steam within the vessels (catheter) described in U.S. Pat. No. 7,753,871-B are adapted to saphenous veins but are not optimized to non-saphenous veins. The catheter used for saphenous trunks obliteration cannot be safely and efficiently used to treat non-saphenous veins like tributaries and perforators because of the length (45 to 60 cm) and low flexibility (has a metallic core) of the current catheter. It is not suitable for veins which are short, very tortuous and with a fragile wall (easy to be perforated) like tributaries and perforators veins. Moreover, the delivery of 70-80 μl water pulses in the SVS device according to U.S. Pat. No. 7,753,871-B is not systematically adapted to all tributaries, specifically to the ones closed to the skin and for smaller veins (tributaries can have smaller diameters compared to saphenous). Finally, the reduction cost of the SVS device for treating non-saphenous veins, is required.
Treatments of non-saphenous varicose veins are currently carried out using 2 techniques:                Ambulatory phlebectomy: removing the vein through small incisions using a “hook”, usually under local or tumescent anesthesia.                    1. This process is time consuming            2. It is often difficult to remove all the veins, especially if they are adhering to the skin, as in areas of lipodermatosclerosis.            3. Some pigmentation of the scars may occur.            4. Phlebectomy remains a relatively invasive method that is not easily accepted by patients as it is painful and surgically wounded. And it can be performed only in a surgical setting (operating room).                        Foam sclerosis consists in injecting in the vein a sclerosing agent mixed with air or another gas, usually CO2.                    1. On larger veins it is often followed by inflammatory reactions, pain and pigmentation of the skin. Thrombus removal can be necessary to treat these incidents.            2. Serious adverse events, such as transient ischemic attacks or ischemic strokes, have been reported with foam sclerotherapy            3. The quantity of foam injected per session is limited (Tegernsee's Consensus, 2006) so several sessions may be necessary, increasing the overall cost of this technique and requiring the patient to undergo several operations.                        
Thus, there is a need for a better way to treat tributary and perforator varicose veins with a procedure that is less time-consuming and that is minimally invasive and painfulness than phlebectomy, as well as less incidents-prone than foam sclerotherapy.